1. Field of the Invention
The invention relates to a laryngeal mask, more particularly to an improved laryngeal mask having a forward guide tab projecting forwardly from a welded edge of an inflatable ring.
2. Description of the Related Art
Laryngeal masks are medical aids that are used to administer anesthetic gases to patients. FIGS. 1 and 2 show a conventional laryngeal mask disclosed in U.S. Pat. No. 5,355,879. As shown, the conventional laryngeal mask includes an airway tube 10, an inflatable ring 20 connected to the airway tube 10, and an inflation flexible tube 30 connected to the inflatable ring 20. The airway tube 10 has an inlet end and an opposite end connected to an inner periphery of the inflatable ring 20 in an oblique manner to define an opening 11. A front end wall of the airway tube 10 at the opening 11 has a forward guide part 12 to facilitate insertion of the laryngeal mask into the patient's throat. The inflatable ring 20 is substantially elliptical, and can be inflated and deflated through the flexible tube 30 by operation of a pump (not shown).
In use, the inflatable ring 20 which has not been inflated is inserted into the patient's throat through the patient's mouth, as shown in FIG. 3. By introducing air into the inflatable ring 20 through the flexible tube 30, the inflatable ring 20 can be inflated to seal around the laryngeal inlet so that there is not any clearance between the patient's throat and the inflatable ring 20. It is necessary that the opening 11 be properly aligned with the laryngeal inlet so that anesthetic gases to be administered can be delivered into the trachea without dispersing to the other parts of the body.
However, as the inflatable ring 20 is inserted into the patient's mouth in a deflated state in actual practice, and as the inflatable ring 20 is made of a soft flexible material, insertion of the inflatable ring 20 into the patient's throat is guided only by the forward guide part 12 at the front end wall of the airway tube 10. However, since the forward guide part 12 is at a distance from a forward end of the inflatable ring 20, the guiding effect is not satisfactory, thereby resulting in difficulty when aligning the opening 11 with the patient's laryngeal inlet and in inconvenient installation. Improper installation of the inflatable ring 20 will, in turn, obstruct supply of air into the inflatable ring 20 such that the latter cannot be fully inflated, thereby resulting in clearances between the inflatable ring 20 and the patient's laryngeal inlet. Thus, the anesthetic gases introduced through the airway tube 10 may disperse to other parts of the patient's body.